esp-hal/esp32-hal/examples/hello_world.rs

#![no_std]
#![no_main]

use core::fmt::Write;

use esp32_hal::{
    clock::ClockControl,
    pac::Peripherals,
    prelude::*,
    timer::TimerGroup,
    RtcCntl,
    Serial,
};
use nb::block;
use panic_halt as _;
use xtensa_lx_rt::entry;

#[entry]
fn main() -> ! {
    let peripherals = Peripherals::take().unwrap();
    let system = peripherals.DPORT.split();
    let clocks = ClockControl::boot_defaults(system.clock_control).freeze();

    let timer_group0 = TimerGroup::new(peripherals.TIMG0, &clocks);
    let mut timer0 = timer_group0.timer0;
    let mut wdt = timer_group0.wdt;
    let mut serial0 = Serial::new(peripherals.UART0);
    let mut rtc_cntl = RtcCntl::new(peripherals.RTC_CNTL);

    // Disable MWDT and RWDT (Watchdog) flash boot protection
    wdt.disable();
    rtc_cntl.set_wdt_global_enable(false);

    timer0.start(1u64.secs());

    loop {
        writeln!(serial0, "Hello world!").unwrap();
        block!(timer0.wait()).unwrap();
    }
}